Inertia starter



Aug. 16, 1955 v- SILBERSTEIN 2,715,396

INEIRTIA STARTER Filed June 9, 1952 United States Patent O INERTIA STARTER Victor Silberstein, London, England Application Inne 9, 1952, Serial N0. 292,500

Claims priority, applicafion Great Britain Inne 12, 1951 8 Claims. (C1. 123-179) This invention relates to inertia starters for internal combustion engines, particularly diesel engines, of the kind comprising a flywheel adapted to be rotated and then coupled to the crankshaft of an engine, and means for decoupling the flywheel of the Starter from the crankshaft when the engine has started.

Inertia starters of th1's ki.nd are nsually provicled With a loose pinion engaged about a threaded shaft and arranged so that, When the starter flywheel is clutched, directly o1 indirectly, to this shaft, the pinion is thrown into engagement With a gear wheel arranged to turn the crankshaft, this gear wheel being generally constituted by the rnain flywheel of the engine and having peripheral teeth for this purpose. starts, the speed of this gear whee1 is increased so that the speed of the loose pinion, now become the driven instead of the driving member, overruns that of the threaded shaft on which it is mounted, and the pinion is automatically screwed out of engagernent With the gear wheel.

Difficulties have, however, arisen in connection with the conventional loose pinion arrangements described in the preceding aragraph, because of the occasional failure of the pinion to engage with the gear wheel during the short period of the startet action, and it is an object of this invention to provide means for making such engagement more certain.

It is a further object of this invention to provide means whereby the engine can be put into a condition for easy starting before the starter flywheel is coupled to the crankshaft, by a combination of scavenging and oilfilm breaking operations.

According to this invention an inertia starter of the kind referred to comprises drive means, preferably for manual drive, a step-up gear connection between the drive means and startet flywheel, a pinion adapted to engage an engine to be started, clutch means between the pinion and Starter flywheel, and an auxiliary drive connection between the drive rneans and said pinion in parallel with said step-up gear connection and clutch, adapted to turn the engine at below starting speed when the pinion is engaged therewith before said clutch is engaged to start the engine.

Preferably, the pinion is mounted on a threaded shaft for screwing into and out of engagement with a toothed rotary engine member, and the auxiliary drive connection is adapted to drive the pinion into said engagernent, rneans such as a light spring pressed against the pinion teeth being providecl to restrain the pinion against rotation whilst it is being so driven into engagernent.

The auxiliary drive connection between said drive means and pinion may incorporate a step-down gear and preferably embodies a one-way clutch.

The connection between the drive means and the startet flywheel may also be nun-reversible and may also be disconnectable without severing the auxiliary drive, so that the latter can be used for turning the engine at a slow speed for adjustment purposes.

When the engine 2715396 Patented Aug. 16, 1955 The clutch between the startet flywheel and pinion is preferably of the type Which operates automatically at a predetermined speed and disengages only after a substantial reduction in speed Preferably, centrifugal gevernors are employed having a spring return and being mounted at the ends of pivoted levers adapted to thrust rotary cam surfaces into engagement in an axial direction when the levers are swung 011 centrifngal motion of the governors.

The accompanying drawing illustrates, in diagrammatic form, one embodiment of this invention.

In the embodiment, a conventional loose pinion 2, engaged about a threaded end of the main starter shaft 3, is located so that it can be brought into engagement with a toothed rim 1 aflixed to the flywheel of the engine to be started (not shown), engagement being efiected by rotating shaft 3 in the direction of the arrow While Preventing pinion 2 from turning by means shown as a light spring 15.

The startet is provided with a handle 17 for manual drive and, when turned in the direction cf the arrow, the drive is transmitted by way of shaft 20, bevel wheels 19, shaft 18, ratchet 14, and spur wheels 16 and 5 to shaft 3, this being a step-down transmission Which causes pinion 2 to engage With toothed rim 1 as described in the preceding aragraph. Stop ring 4 prevents movement of pinion 2 beyond the engaged position.

Shaft 18 also serves to transmit, by way of ratchet 21, spur wheels 13 and 12, shaft 11 and key 10, drive to starter flywheel 7. The latter is slidaole 011 shaft 11 in an axial direction. As described above centrifugal means comprising weighted levers 8 and spring 9 am provided and are arranged so that, When flywheel 7 reaches a predetermined angular velocity, it is moved along shaft 11 into clutching engagement With a clutch rnember 6 fastened to shaft 3, the direction of the rotation being the same as that occasioned by the auxiliary drive described in the preceding aragraph.

In a practical arrangement, shaft 18 may have to make several hundred revolutions before manual actuation of handle 17 brings flywheel 7 to the angular velocity needed to cause clutching, during Which time pinion 2 is moved fully into the engaged position and turns the engine slcwly for a few revolutions, This has the particular advantage that scavenging and priming of the engine is effected immediately prior to each starting operation.

Inertia starters in accordance With this invention are especially useful in conjunction With diesel engines, such as are found in farrn tractors, andit is a characteristic of these engines that they are difiicult to turn for adjustment or other purposes. By incorporating means for interrupting the main drive without interrupting the auxiliary drive, the desired rovision for slow and comtrolled turning of the engine is made readily available; where a ratchet is inserted in the main drive, such as ratchet wheel 21 shown in the accompanying drawing, this rneans may constitute means for disengaging the ratchet, and is illustrated diagrammatically as member 22.

lt will be understood that various alterations may be made to the illustrated embodiment without departing from the scope of this invention. Thus, instead of having a common shaft 18 between the main and auxiliary drives, the latter may take the form of a belt drive, handle 20 being disconnectable from bevels 19 by means of ratchet 22, transposed for this purpose to a position between the handle and bevels 19 so that such disconnection can be eflected merely by pulling on the handle.

I claim:

1. An inertia starter for engines comprising a startet flywheel, drive means, operatively connected With the starter flywheel, a pinion adapted to engage the engine to be started, clutch means located intermediate the pinion andstarterflywheel, and an auxiliary drive operatively c0nn'ected betWeen said drive 'm6ans and the pinioi1in parallel with said connection to the st'arter flywheel and the clutch m'eans adaptcd to turn the :i:lgine at below starting spe'ed when the pinion is engaged 'with the engine, before said clutch means is engaged.

2. A startcr as set forth in cla1'm 1, wherein the pini0n is mounted on a threaded shaft' for screwing into and out of engagement With a toothed rotary memberconnected to the engine, and wherein the auxiliary drivk: is dapted to driv'e the pinion into said engzigeme'nt. v

3. A startet as set fortl1 in claim 2, whereln means coopera'teswith the pinion teeth to restrainthe pinion against r'otation the pinion is being driven int0 engagement With the 'rotary member. 4. A starten as set forth in claim l, wherein the auxiliary drive connection includes a one-way clutch.

'5. A starter as set forth in claim 1 wherein the con disconuectable independently of the auxiliary drive' between the drive means and the pinion.

6. A startet as set forth in claim 1, wherein the auxiliary drive includes a step-down gear.

7. A starter as set forth in claim 1, wherein the clutch meanslocated intermediate the pinion and Starter fiywheel operates automatically at a prcdeterminecl speed and disengages only after a substantial drop in speed.

8. A starter as set forth in claim 7 wherein the clutch means comprlses a rotary axially slidable clutch 111cmber, a complementary mernber, and centrifugal governors having a spring return and being mounted at the ends cf pivotd levers adapted to slide said slidable member into engagernent With the complementary member when the levers are swung 011 centrifugal niotion f the governors.

Refrences Cted in the file of this patent FOREIGN PATENTS 900,419 France Oct. 2, 1944 

